Wind power generation systems are known in the art (a) which include a power generation unit having an elastically deformable base material in the shape of a longitudinal flat plate and a piezoelectric element disposed on the base material, (b) in which the power generation unit is held at its both longitudinal ends and is placed at a position where wind blows, and which generates electricity as the power generation unit is vibrated so that an intermediate portion of the power generation unit in a longitudinal direction reciprocates in the thickness direction of the power generation unit and the piezoelectric element is repeatedly bent and deformed by the vibration. The system described in Patent Document 1 is an example of such wind power generation systems and uses a thin piezoelectric ceramic plate as the piezoelectric element. A piezoelectric film made of resin as described in Patent Document 2 may also be used as the piezoelectric element.